When Do You Round Up or Down with 5?

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Discussion Overview

The discussion revolves around the rules and conventions for rounding numbers that end in five, particularly in the context of rounding 5.65 to one decimal place. Participants explore different approaches to rounding, including traditional methods and those used in specific fields like computer science.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant expresses confusion about when to round up or down when a number ends in five, specifically questioning if 5.65 should round to 5.6 or 5.7.
  • Another participant states that typically, 5 is rounded up, but notes that in computer science, rounding down everything including .9 is common, and rounding .5 to the nearest even number is also practiced to reduce rounding errors.
  • A different participant shares their experience of always rounding up when the last digit is between 5 and 9, asserting that 5.65 should round to 5.7 unless a specific rule dictates otherwise.
  • Another participant advocates for rounding 5 to the nearest even number, explaining that this method minimizes skew over multiple rounding events.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the correct approach to rounding numbers that end in five, with multiple competing views presented regarding whether to round up, down, or to the nearest even number.

Contextual Notes

Participants reference different conventions and contexts for rounding, indicating that the rules may vary based on the situation or field of study.

mcnealymt
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Homework Statement


I'm very confused as to when your supposed to add up or down when a number follows a five.




Homework Equations





The Attempt at a Solution


For instance, round 5.65 to 1 decimal. THe answer is 5.6, isn't this because when an even number is followed by a five you round down?

However, I was always told that 5.65 rounded to 1 decimal place is simply 5.7
 
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Usually, 5 is rounded up.
In computer science, "round down everything (including .9)" is common, and "round .5 to the nearest even number" is used, too (this can reduce rounding errors later).
 
I've always rounded up when the last digit is 5-9. Thus 5.65 = 5.7. In my experience, this is customary unless a special rule is imposed for a certain situation.

There is a lengthy article here about different types of rounding:
http://en.wikipedia.org/wiki/Rounding
 
I've always done rounding 5 to the even number. Reasoning being that over the course of multiple rounding events you will round some up and some down thereby minimizing the skew to either direction.
 

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